Surgical stapling apparatus including releasable surgical buttress

ABSTRACT

A staple cartridge for use with a surgical stapling apparatus includes a cartridge body including a tissue contacting surface defining a plurality of staple retaining slots, a staple disposed within each staple retaining slot of the cartridge body, and a substantially circular buttress. The buttress includes an inner portion, an outer portion, and a middle portion extending between the inner portion and the outer portion. At least one stiffened region joins the buttress to the tissue contacting surface of the cartridge body. The inner portion, the middle portion, the outer portion, and the at least one stiffened region are all formed from a common material.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation application which claims the benefit of and priority to U.S. patent application Ser. No. 16/437,045, filed on Jun. 11, 2019, which is a Divisional application which claims the benefit of and priority to U.S. patent application Ser. No. 15/168,924, filed on May 31, 2016 (now U.S. Pat. No. 10,357,249), which is a Division application which claims the benefit of and priority to U.S. patent application Ser. No. 13/325,481, filed on Dec. 14, 2011 (now U.S. Pat. No. 9,351,731), the entire disclosures of each of which is hereby incorporated by reference herein.

BACKGROUND Technical Field

The present disclosure relates to surgical stapling apparatus including surgical buttresses which are releasably attached to the surgical stapling apparatus, and in particular, to surgical stapling apparatus having surgical buttresses having at least a portion with increased rigidity and/or stability.

Background of Related Art

Surgical stapling apparatus are employed by surgeons to sequentially or simultaneously apply one or more rows of fasteners, e.g., staples or two-part fasteners, to body tissue for the purpose of joining segments of body tissue together. Such apparatus generally include a pair of jaws or finger-like structures between which the body tissue to be joined is placed. When the stapling apparatus is actuated, or “fired”, longitudinally moving firing bars contact staple drive members in one of the jaws. The staple drive members push the surgical staples through the body tissue and into an anvil in the opposite jaw which forms the staples. If tissue is to be removed or separated, a knife blade can be provided in the jaws of the apparatus to cut the tissue between the lines of staples.

A number of surgical stapling apparatus rely on secondary materials, such as adhesives or mounting structures (e.g., sutures) to maintain a surgical buttress on the stapling apparatus. The use of additional materials may leave a residue in the body after implantation and/or require increased firing forces as each material must be transected by the knife blade to detach the surgical buttress from the stapling apparatus.

It would be desirable to provide a buttress that may be releasably secured to a surgical stapling apparatus without the need for a secondary material or mounting structure.

Buttress materials that are formed from non-woven or mesh-like materials are known. These materials are relatively flexible and can shift on the surgical stapling apparatus. It may be desirable in at least certain applications to provide a buttress that has a stiffer construction or at least some stiffer portions to facilitate the placement of the buttress on the apparatus, or the placement of the buttress on tissue, or both.

SUMMARY

According to an aspect of the present disclosure, a staple cartridge for use with a surgical stapling apparatus includes a cartridge body including a tissue contacting surface defining a plurality of staple retaining slots, a staple disposed within each staple retaining slot of the cartridge body, and a substantially circular buttress. The buttress includes an inner portion, an outer portion, and a middle portion extending between the inner and outer portions. At least one stiffened region joins the buttress to the tissue contacting surface of the cartridge body. The inner portion, the middle portion, the outer portion, and the at least one stiffened region are all formed from a common material.

The stiffened region may be disposed in any portion of the buttress. In embodiments, at least the outer portion of the buttress includes the stiffened region. In embodiments, at least the inner portion of the buttress includes the stiffened region. In embodiments, the stiffened region includes a plurality of spokes extending radially outward from the inner portion of the buttress to the outer portion of the buttress. In some embodiments, the stiffened region may be disposed radially inward of the staple retaining slots. Alternatively, or additionally, the stiffened region may be disposed radially outward of the staple retaining slots.

The stiffened region may include ruffles. The ruffles may be folds, pleats, undulations, corrugations, creases, ridges, or bends. The stiffened region may be a localized crosslinked region of the buttress. The buttress may include a stiffening agent.

The buttress may include a flange. In embodiments, the outer portion of the buttress includes a terminal flange extending around an outer perimeter of the tissue contacting surface of the cartridge body. In such embodiments, the stiffened region may extend through the terminal flange. The terminal flange may be adjoined to an outer surface of the cartridge body.

The buttress material may include a central opening. The stiffened region may be concentric with the central opening. In embodiments, the inner portion of the buttress may include an interior flange annularly extending into the central opening. In such embodiments, the stiffened region may extend through the interior flange. The interior flange may be adjoined to an inner surface of the cartridge body.

Accordingly to another aspect of the present disclosure, a surgical stapling apparatus includes a tubular body portion, an anvil assembly, a cartridge body, a staple, and a substantially circular buttress. The tubular body portion of the surgical stapling apparatus has a distal end and a shaft with a connection portion, and the anvil assembly includes an anvil plate having staple forming recesses and a shaft connectable with the connection portion. The cartridge body is receivable in the distal end of the tubular body portion and includes a tissue contacting surface defining a plurality of staple retaining slots, the staple retaining slots defining at least two annular rows of staple retaining slots. A staple is disposed within each staple retaining slot of the cartridge body. The buttress includes an inner portion, an outer portion, and a middle portion extending between the inner portion and the outer portion. At least one stiffened region joins the buttress to the tissue contacting surface. The inner portion, the middle portion, the outer portion, and the at least one stiffened region are all formed from a common material.

Accordingly to yet another aspect of the present disclosure, a surgical stapling apparatus includes a tubular body portion, an anvil assembly, a cartridge body, a staple, and a substantially circular buttress. The tubular body portion of the surgical stapling apparatus has a distal end and a shaft with a connection portion, and the anvil assembly includes an anvil plate having staple forming recesses and a shaft connectable with the connection portion. The cartridge body is receivable in the distal end of the tubular body portion and includes a tissue contacting surface defining a plurality of staple retaining slots, the staple retaining slots defining at least two annular rows of staple retaining slots. A staple is disposed within each staple retaining slot of the cartridge body. The buttress includes at least one buttress region and at least one stiffened region formed from a common material.

The stiffened region may be disposed in any portion of the buttress. In embodiments, the stiffened region is disposed about an outer portion of the buttress. In embodiments, the stiffened region is disposed about an inner portion of the buttress. In embodiments, the stiffened region includes a plurality of spokes extending radially outward from an inner portion of the buttress to an outer portion of the buttress. In some embodiments, the stiffened region may be disposed radially inward of the staple retaining slots. Alternatively, or additionally, the stiffened region may be disposed radially outward of the staple retaining slots.

The stiffened region may include ruffles. The stiffened region may be a localized crosslinked region of the buttress. The buttress may include a stiffening agent.

The buttress may include a flange. In embodiments, the buttress includes a terminal flange extending around an outer perimeter of the tissue contacting surface of the cartridge body. In such embodiments, the stiffened region may extend through the terminal flange. The terminal flange may be adjoined to an outer surface of the cartridge body.

The buttress material may include a central opening. The stiffened region may be concentric with the central opening. In embodiments, the buttress may include an interior flange annularly extending into the central opening. In such embodiments, the stiffened region may extend through the interior flange. The interior flange may be adjoined to an inner surface of the cartridge body.

According to another aspect of the present disclosure, a surgical stapling apparatus includes a tubular body portion, an anvil assembly, a cartridge body, a staple, and a substantially circular buttress. The tubular body portion of the surgical stapling apparatus has a distal end and a shaft with a connection portion, and the anvil assembly includes an anvil plate having staple forming recesses and a shaft connectable with the connection portion. The cartridge body is receivable in the distal end of the tubular body portion and includes a tissue contacting surface defining a plurality of staple retaining slots, the staple retaining slots defining at least two annular rows of staple retaining slots. A staple is disposed within each staple retaining slot of the cartridge body. The buttress includes at least one buttress material and at least one stiffened region. The stiffened region is formed by adding a stiffening agent to the buttress material, the stiffening agent being a sugar, a salt, a starch, a hydrogel, a degradable polymer, or combinations thereof.

For example, sugars may include tahalose, sucrose, galatose, and glucose; salts may include sodium chloride, potassium chloride, and sodium phosphate; hydrogels may include degradable polyethylene glycol or poly(2-hydroxyethyl methacrylate); and degradable polymers may include poloxamers or polyhydroxy acids. In embodiments, the polyhydroxy acids are glycolide, lactide, trimethylene carbonate, p-dioxanone, ε-caprolactone, or combinations thereof. The stiffening agent may be coated on the buttress and/or impregnated therein.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the presently disclosed surgical stapling apparatus and surgical buttress are described herein with reference to the accompanying drawings, wherein:

FIG. 1A is a perspective view of an illustrative embodiment of a surgical stapling apparatus and surgical buttress (shown separated from a staple cartridge assembly of the surgical stapling apparatus) in accordance with an embodiment of the present disclosure;

FIG. 1B is a cross-sectional view of a portion of the surgical stapling apparatus of FIG. 1A including a surgical buttress positioned within an intestinal area;

FIG. 1C is a top view of the surgical buttress depicted in FIG. 1B, illustrating its attachment to the surgical stapling apparatus of FIG. 1A;

FIGS. 2A-2D are top views of surgical buttresses in accordance with other embodiments of the present disclosure;

FIG. 2E is a perspective view of a surgical buttress in accordance with an embodiment of the present disclosure;

FIGS. 3A and 3B are cross-sectional views of a staple cartridge of the surgical stapling apparatus and a surgical buttress in accordance with an exemplary process of forming the stiffened regions in accordance with an embodiment of the present disclosure;

FIG. 4 is a schematic side view of a staple cartridge assembly and surgical buttress in accordance with an embodiment of the present disclosure;

FIG. 5A is a perspective view, with parts separated, of a staple cartridge assembly and surgical buttress in accordance with an embodiment of the present disclosure;

FIG. 5B is a schematic side view of the surgical buttress of FIG. 5A positioned on the staple cartridge assembly in accordance with an embodiment of the present disclosure;

FIG. 5C is a schematic perspective view of the surgical buttress of FIG. 5A positioned on the staple cartridge assembly in accordance with another embodiment of the present disclosure;

FIG. 6A is a perspective view, with parts separated, of a staple cartridge assembly and surgical buttress in accordance with an embodiment of the present disclosure;

FIG. 6B is a schematic side view of the surgical buttress of FIG. 6A positioned on the staple cartridge assembly in accordance with an embodiment of the present disclosure;

FIG. 6C is a schematic perspective view of the surgical buttress of FIG. 6A positioned on the staple cartridge assembly in accordance with another embodiment of the present disclosure;

FIGS. 7A-7C are top views of surgical buttresses, illustrating their attachment to the surgical stapling apparatus of FIG. 1A, in accordance with other embodiments of the present disclosure;

FIG. 8A is a perspective view of an illustrative embodiment of a surgical stapling apparatus in accordance with an embodiment of the present disclosure;

FIG. 8B is a perspective view, with parts separated, of the staple cartridge assembly of the surgical stapling apparatus and of the surgical buttress of FIG. 8A;

FIG. 9 is a perspective view of another illustrative embodiment of a surgical stapling apparatus for use with a surgical buttress of the present disclosure; and

FIG. 10 is a perspective view of yet another illustrative embodiment of a surgical stapling apparatus for use with a surgical buttress of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments of the present disclosure are discussed herein below in terms of surgical buttresses for use with surgical stapling apparatus. The surgical buttresses described herein may be used in joining the edges of wound tissue utilizing a surgical stapling apparatus which has at least one surgical buttress mounted thereon. The at least one surgical buttress is joined to the surgical stapling apparatus and includes at least one stiffened region. The at least one stiffened region can adhere, or otherwise be used to connect, the surgical buttress to the surgical stapling apparatus. In embodiments, actuation of a knife provides a force that impinges against the surgical buttress and displaces the buttress by a sufficient amount to weaken or break the bond created by the stiffened region between the surgical buttress and the surgical stapling apparatus, thereby releasing the surgical buttress therefrom before substantial cutting of the buttress material. In other embodiments, cutting of the surgical buttress by the knife blade releases a portion of the surgical buttress that is free of the stiffened region. Thus, the present disclosure describes surgical buttresses, surgical stapling apparatus supporting said surgical buttresses, and methods and mechanisms for using the same.

It should be understood that a variety of surgical stapling apparatus may be utilized with a surgical buttress of the present disclosure. For example, circular stapler configurations may be utilized, such as, for example those including end-to-end anastomosis staplers having a circular cartridge and anvil (see, e.g., commonly owned U.S. Pat. No. 5,915,616, entitled “Surgical Fastener Applying Apparatus,” the entire content of which is incorporated herein by this reference), and linear stapler configurations, such as, for example those including Duet TRS™ reloads and staplers with Tri-Staple™ technology, available through Covidien, which maintain a principal place of business at 555 Long Wharf Drive, North Haven, Conn. 06511, and transverse anastomosis staplers, such as, for example, EEA™ instruments, CEEA™ instruments, GIA™ instruments, EndoGIA™ instruments, and TA′ instruments, also available through Covidien. It should also be appreciated that the principles of the present disclosure are equally applicable to surgical staplers having alternate configurations, such as, for example, laparoscopic staplers (see, e.g., commonly owned U.S. Pat. Nos. 6,330,965 and 6,241,139, each entitled “Surgical Stapling Apparatus,” the entire contents of each of which being incorporated herein by this reference) and transverse anastomosis staplers (see, e.g., commonly owned U.S. Pat. Nos. 5,964,394 and 7,334,717, each entitled “Surgical Fastener Applying Apparatus”, the entire contents of each of which being incorporated herein by this reference).

Embodiments of the presently disclosed surgical buttress and surgical stapling apparatus will now be described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical elements. In the following discussion, the terms “proximal” and “trailing” may be employed interchangeably, and should be understood as referring to the portion of a structure that is closer to a clinician during proper use. The terms “distal” and “leading” may also be employed interchangeably, and should be understood as referring to the portion of a structure that is further from the clinician during proper use. As used herein, the term “patient” should be understood as referring to a human subject or other animal, and the term “clinician” should be understood as referring to a doctor, nurse, or other care provider and may include support personnel.

Referring now to FIGS. 1A and 1B, there is disclosed an exemplary surgical stapling apparatus or surgical stapler 10 for use in stapling tissue and applying a buttress material or surgical buttress to the tissue. Surgical stapling apparatus 10 generally includes a handle assembly 12 having at least one pivotable actuating handle member 33, and an advancing member 35. Extending from handle member 12, there is provided a tubular body portion 14 which may be constructed so as to have a curved shape along its length. Body portion 14 terminates in a staple cartridge assembly 32 which includes an annular array of staple retaining slots 52 having a staple 50 disposed in each one of staple retaining slots 52. Positioned distally of staple cartridge assembly 32 there is provided an anvil assembly 20 including an anvil member 21 and a shaft 23 operatively associated therewith for removably connecting anvil assembly 20 to a distal end portion of stapling apparatus 10.

Staple cartridge assembly 32 may be fixedly connected to the distal end of tubular body portion 14 or may be configured to concentrically fit within the distal end of tubular body portion 14. Typically, staple cartridge assembly 32 includes a staple pusher 64 including a proximal portion having a generally frusto-conical shape and a distal portion defining two concentric rings of peripherally spaced fingers (not shown), each one of which is received within a respective staple retaining slot 52.

A knife 30, substantially in the form of an open cup with the rim thereof defining a knife blade 31, is disposed within staple cartridge assembly 32 and mounted to a distal surface of a staple pusher 64. The knife 30 is disposed radially inward of the annular arrays of staples 50. Accordingly, in use, as the staple pusher 64 is advanced, the knife 30 is also advanced axially outward.

Reference may be made to commonly owned U.S. Pat. No. 5,915,616 to Viola et al., referenced above, for a detailed discussion of the construction and operation of an annular stapling device, the disclosure of which is hereby incorporated by reference herein.

A surgical buttress 24 is releasably attached to the staple cartridge assembly 32 by at least one stiffened region 40 that bonds the surgical buttress 24 to a tissue contacting/facing surface of staple cartridge assembly 32. It should be understood that while the surgical buttress 24 is described herein as being associated with the staple cartridge assembly 32, the surgical buttress 24 may, alternatively or additionally, be associated with the anvil assembly 20. Surgical buttress 24 is provided to reinforce and seal staple lines applied to tissue by surgical stapling apparatus 10. Surgical buttress 24 may be configured into any shape, size, or dimension suitable to fit any surgical stapling, fastening, or firing apparatus.

Surgical buttress 24 is fabricated from a biocompatible material which is a bioabsorbable or non-absorbable, natural or synthetic material. It should of course be understood that any combination of natural, synthetic, bioabsorbable, and non-bioabsorbable materials may be used to form the surgical buttress. In embodiments, the entire surgical buttress 24, or portions thereof, may be fabricated from the same material, or combination of materials that is homogeneous throughout the surgical buttress 24. In other embodiments, the surgical buttress 24 may be formed of different materials.

The surgical buttress 24 may be porous, non-porous, or combinations thereof. It is also envisioned that surgical buttress 24 described herein may contain a plurality of layers in which any combination of non-porous and porous layers may be configured as discussed further below. For example, surgical buttress may be formed to include multiple non-porous layers and porous layers that are stacked in an alternating manner. In another example, surgical buttress may be formed in a “sandwich-like” manner wherein the outer layers of the surgical buttress include porous layers and the inner layers are non-porous layers. It is further envisioned that non-porous and porous layers may be positioned in any order relative to the tissue contacting surfaces of the staple cartridge/anvil assembly. Examples of multilayered surgical buttresses are disclosed in U.S. Patent Application Publication No. 2009/0001122 filed Jun. 27, 2007, entitled “Buttress and Surgical Stapling Apparatus,” the entire disclosure of which is incorporated by reference herein.

Some non-limiting examples of materials from which non-porous and/or porous layers of surgical buttress 24 may be made include, but are not limited to, poly(lactic acid), poly (glycolic acid), poly (hydroxybutyrate), poly (phosphazine), polyesters, polyethylene glycols, polyethylene oxides, polyacrylamides, polyhydroxyethylmethylacrylate, polyvinylpyrrolidone, polyvinyl alcohols, polyacrylic acid, polyacetate, polycaprolactone, polypropylene, aliphatic polyesters, glycerols, poly(amino acids), copoly (ether-esters), polyalkylene oxalates, polyamides, poly (iminocarbonates), polyalkylene oxalates, polyoxaesters, polyorthoesters, polyphosphazenes and copolymers, block copolymers, homopolymers, blends, and combinations thereof.

In embodiments, natural biological polymers are used in forming a non-porous layer of the surgical buttress. Suitable natural biological polymers include, but are not limited to, collagen, gelatin, fibrin, fibrinogen, elastin, keratin, albumin, hydroxyethyl cellulose, cellulose, oxidized cellulose, hydroxypropyl cellulose, carboxyethyl cellulose, carboxymethyl cellulose, chitan, chitosan, and combinations thereof. In addition, the natural biological polymers may be combined with any of the other polymeric materials described herein to produce a non-porous layer of the surgical buttress.

In embodiments, collagen of human and/or animal origin, e.g., type I porcine or bovine collagen, type I human collagen or type III human collagen, may be used to form a non-porous layer of the surgical buttress. In embodiments, a non-porous layer of the surgical buttress according to the present disclosure is made of collagen which is oxidized or a mixture in any proportions of non-oxidized and oxidized collagens.

The use of non-porous layer(s) in the surgical buttress may enhance the ability of the surgical buttress to resist tears and perforations during the manufacturing, shipping, handling, and stapling processes. Also, the use of a non-porous layer in the surgical buttress may also retard or prevent tissue ingrowth from surrounding tissues thereby acting as an adhesion barrier and preventing the formation of unwanted scar tissue. Thus, in embodiments, the non-porous layer(s) of the surgical buttress may possess anti-adhesion properties.

A non-porous layer of the surgical buttress may be formed using techniques within the purview of those skilled in the art, such as casting, molding, and the like.

Any of the porous layers of the surgical buttress may have openings or pores over at least a portion of a surface thereof. As described in more detail below, suitable materials for forming a porous layer include, but are not limited to, fibrous structures (e.g., knitted structures, woven structures, non-woven structures, etc.) and/or foams (e.g., open or closed cell foams). In embodiments, the pores may be in sufficient number and size so as to interconnect across the entire thickness of the porous layer. Woven fabrics, knitted fabrics, and open cell foam are illustrative examples of structures in which the pores can be in sufficient number and size so as to interconnect across the entire thickness of the porous layer. In embodiments, the pores may not interconnect across the entire thickness of the porous layer, but rather may be present at a portion thereof. Thus, in some embodiments, pores may be located on a portion of the porous layer, with other portions of the porous layer having a non-porous texture. Those skilled in the art reading the present disclosure will envision a variety of pore distribution patterns and configurations for the porous layer. Closed cell foam or fused non-woven materials are illustrative examples of structures in which the pores may not interconnect across the entire thickness of the porous layer.

Where a porous layer of the surgical buttress is fibrous, the fibers may be filaments or threads suitable for knitting or weaving or may be staple fibers, such as those frequently used for preparing non-woven materials. Suitable techniques for making fibrous structures are within the purview of those skilled in the art. The buttress material may be made using non-woven processes, including processes disclosed in U.S. patent application Ser. No. 13/293,215, filed Nov. 10, 2011, and entitled Hydrophilic Medical Devices, the disclosure of which is hereby incorporated by reference herein.

Where a porous layer of the surgical buttress is a foam, the porous layer may be formed using any method suitable to forming a foam or sponge including, but not limited to, the lyophilization or freeze-drying of a composition. Suitable techniques for making foams are within the purview of those skilled in the art.

The origin and types of collagens that may be used to form the porous layer are the same as those indicated above for the non-porous layer. However, the oxidized or non-oxidized collagen may be lyophilized, freeze-dried, or emulsified in the presence of a volume of air to create a foam and then freeze-dried, to form a porous compress.

In embodiments, a porous layer of the surgical buttress may be made from denatured collagen or collagen which has at least partially lost its helical structure through heating or any other method. The term “denatured collagen” means collagen which has lost its helical structure. The collagen used for the porous layer as described herein may be native collagen or atellocollagen. The collagen may have been previously chemically modified by oxidation, methylation, succinylation, ethylation, or any other known process.

The porous layer(s) may enhance the ability of the surgical buttress to absorb fluid, reduce bleeding, and seal the wound. Also, the porous layer(s) may allow for tissue ingrowth to fix the surgical buttress in place.

As illustrated in the current embodiment, and shown in FIGS. 1B and 1C, surgical buttress 24 includes a radially inner portion 42 defining an aperture 29 to receive shaft 23 of anvil assembly 20, a radially outer portion 46, and a radially middle portion 44 extending between the inner portion 42 and the outer portion 46. Stiffened region 40 is provided in at least a portion of the surgical buttress 24 and is configured to reduce shifting of the buttress or a portion of the buttress in relation to the staple retaining slots 52. The stiffened region 40 may be configured to releasably attach the surgical buttress 24 to the staple cartridge assembly 32.

For example, stiffened region 40 of surgical buttress 24 releasably attaches the staple cartridge assembly 32 in a manner which allows the surgical buttress 24 to be removed or released from the staple cartridge assembly 32 upon actuation of the knife 30. Accordingly, the stiffened region 40 is formed with a bond strength that is strong enough to hold the buttress 24 onto the staple cartridge assembly 32, but is weak enough to break free of the staple cartridge assembly 32 when the knife 30 impacts or penetrates the surgical buttress 24 to facilitate the release of the stiffened region 40 from the tissue contact surface 23 and thus, the surgical buttress 24 upon firing of surgical stapling apparatus 10.

As illustrated, stiffened region 40 is provided in the outer portion 46 of the surgical buttress 24 and bonds the surgical buttress 24 to the inwardly facing or tissue contacting surface 26 of the staple cartridge assembly 32. While the stiffened region 40 is shown as continuously extending around the outer portion 46 of the surgical buttress 24, it should be understood that stiffened region 40 may be discontinuous and include a plurality of stiffened regions 40 a attaching the surgical buttress 24 a to the surgical stapling apparatus 10, such as in the configuration illustrated in FIG. 2A, for example. In embodiments, the stiffened region 40, 40 a may be disposed radially outward of the staple retaining slots 52 (FIGS. 1A and 1B).

Other configurations of the stiffened region 40 may be utilized to retain the surgical buttress 24 on the staple cartridge assembly 32. A stiffened region may be provided in other portions of a surgical buttress, such as, for example, in the inner portion as shown in FIG. 2B. The buttress shown in FIG. 2B can be part of any of the embodiments disclosed herein. In particular, FIG. 2B illustrates a stiffened region 40 b extending continuously around an inner portion 42 of surgical buttress 24 b. In other embodiments, a stiffened region 40 c may be discontinuous as illustrated in FIG. 2C, for example. The buttress shown in FIG. 2C can be part of any of the embodiments disclosed herein. While stiffened region 40 c is illustrated as a plurality of circular regions, stiffened region 40 c may be formed of any number of suitably shaped and sized regions. In embodiments, the stiffened region 40 b, 40 c may be disposed radially inward of the staple retaining slots 52 (FIGS. 1A and 1B).

FIG. 2D illustrates a stiffened region 40 d including a plurality of spokes extending radially outward from the inner portion 42 to the outer portion 46 of the surgical buttress 24 d. The buttress shown in FIG. 2D can be part of any of the embodiments disclosed herein. While the spokes of the stiffened region 40 d are illustrated as tapering from the inner portion 42 to the outer portion 46 of the surgical buttress 24, it should be understood that the spokes of the stiffened region 40 d may taper from the outer portion 46 to the inner portion 42 of the surgical buttress 24, or be of uniform or changing width from the outer portion 46 to the inner portion 42.

FIG. 2E illustrates a surgical buttress 24 e in which the stiffened region 40 e extends throughout the inner, outer, and middle portions 42, 44, 46 thereof to form ruffles 41. The buttress shown in FIG. 2E can be part of any of the embodiments disclosed herein. In such embodiments, the ruffles 41 of the stiffened region 40 e may be folds, pleats, undulations, corrugations, creases, ridges, bends, or include other fluctuations in the surface of the surgical buttress 24 e to provide radial stability to the surgical buttress 24 e relative to the staple cartridge assembly 32.

It is envisioned that other configurations, as well as combinations of the embodiments described above, may be utilized to form the stiffened region of a surgical buttress. For example, a surgical buttress may include a stiffened region in both the inner and outer portions of the surgical buttress, or may include ruffles in only a portion thereof. Other configurations will be readily apparent to those skilled in the art. It is envisioned that the number of stiffened regions, stiffened region size, positioning, and spacing can be varied to optimize the attachment of the surgical buttress to the surgical stapling apparatus, as well as to minimize the detachment force required during firing.

The stiffened regions may be formed by applying pressure and/or heat to compress the buttress, or a portion thereof. The pressure and heat may be used to join a surgical buttress to a surgical stapling apparatus, or may be applied during a manufacturing process prior to affixing of the surgical buttress to the surgical stapling apparatus. In embodiments, stiffened regions may be formed by melt pressing, heat staking, and the like. In embodiments in which a fibrous woven or non-woven buttress material is utilized, heat staking the fibers of the surgical buttress will cause the fibers to substantially coalesce or bond to create stiffened regions in the desired portions of the surgical buttress.

As illustrated in FIGS. 3A and 3B, a heat staking apparatus 1000, or the like, is illustrated for attaching a surgical buttress 24 to a staple cartridge assembly 32. The staple cartridge assembly 32 and surgical buttress 24 are placed within a retaining channel 1022 of base 1020 of heat staking apparatus 1000. Heat staking apparatus 1000 includes a compression device 1010 operably connected to a generator (not shown) for activating at least one heating element as is known in the art such that when a die plate 1012 contacts the surgical buttress 24 with a desired amount of pressure, a combination of the desired amount of pressure and/or thermal energy from the compression device 1010 joins the surgical buttress 24 to the staple cartridge assembly 32, forming stiffening region 40. Die 1012 may define a patterned surface 1014 including projections 1016 for forming individual stiffened regions 40 on the surgical buttress 24. Projections 1016 provide small contact surfaces so that the energy delivered by the compression device 1010 is concentrated over a small area. The projections are positioned to form stiffened region 40 and, as described above, may be any shape and size depending on the desired configuration.

In embodiments, the die plate 1012 may assume a concave shape so that the surgical buttress 24 f, as shown in FIG. 4, may be heat pressed into a dome shape over staple cartridge assembly 32 to provide structural rigidity to the surgical buttress 24 f.

In other embodiments, the stiffened regions may be formed by coating or impregnating the buttress material with a stiffening agent. The stiffening agent is biocompatible and may be dissolvable and/or degradable in vivo. Stiffening agents include, for example: sugars such as tehalose, sucrose, galatose, and glucose; salts such as sodium chloride, potassium chloride, and sodium phosphate; hydrogels such as degradable polyethylene glycol (PEG) or poly(2-hydroxyethyl methacrylate) (pHEMA); and degradable polymer coatings such as those including poloxamers as well as polyhydroxy acids prepared from lactone monomers such as glycolide, lactide, trimethylene carbonate, p-dioxanone, ε-caprolactone, and combinations thereof. In some embodiments, the degradable polymer coating may include a copolymer of glycolic acid and trimethylene carbonate. In embodiments, the degradable polymer coating may include a copolymer of l-lactide and glycolide, and in some embodiments, the coating may include from about 70% l-lactide and about 30% glycolide. In embodiments, the coating may include a copolymer of glycolide and e-caprolactone, and in some embodiments, from about 15% glycolide and about 85% e-caprolactone. The stiffening agent may impart rigidity to the surgical buttress for several minutes after contact with body fluids after insertion of the surgical stapling apparatus into the body cavity, leaving the buttress material supple after implantation.

Referring again to FIGS. 1A and 1B, surgical stapling apparatus 10 and detachable anvil assembly 20 are used in an anastomosis procedure to effect joining of intestinal sections 1 and 2. The anastomosis procedure is typically performed using minimally invasive surgical techniques including laparoscopic means and instrumentation. At the point in the procedure shown in FIG. 1B, a diseased intestinal section has been previously removed, anvil assembly 20 has been applied to the operative site either through a surgical incision or transanally and positioned within intestinal section 2, and tubular body portion 14 of surgical stapling apparatus 10 has been inserted transanally into intestinal section 1. Intestinal sections 1 and 2 are also shown temporarily secured about their respective components (e.g., shaft 23 of anvil assembly 20, and the distal end of tubular body portion 14) by conventional means such as a purse string suture “P”.

Thereafter, the clinician maneuvers anvil assembly 20 until the proximal end of shaft 23 is inserted into the distal end of tubular body portion 14 of surgical stapling apparatus 10, wherein a mounting structure within the distal end of tubular body portion 14 engages shaft 23 to effect the mounting. Anvil assembly 20 and tubular body portion 14 are then approximated to approximate intestinal sections 1, 2. Surgical stapling apparatus 10 is then fired. The staples 50 are fired, effecting stapling of intestinal sections 1, 2 to one another. The force of the knife 30 being fired breaks the bonds between the surgical buttress 24 and the staple cartridge assembly 32 created by stiffened region 40 thereby releasing the surgical buttress 24 from the staple cartridge assembly 32, and cutting the portion of tissue and surgical buttress 24 disposed radially inward of the knife 30, to complete the anastomosis.

Referring now to FIGS. 5A-6C, the surgical buttress may include an outer and/or inner flange. As shown in FIG. 5A-5C, surgical buttress 24 may include a terminal flange 21 a extending around an outer perimeter of the tissue contacting surface 23 of the staple cartridge assembly 32. In embodiments, as shown in FIG. 5B, terminal flange 21 a may be secured to a side surface 25 a of the staple cartridge assembly 32. Terminal flange 21 a of surgical buttress 24 may be joined to an outer side surface 25 a of the staple cartridge assembly 32 via stiffened region 40 by melt pressing, heat staking, and the like, as described above. Alternatively, as shown in FIG. 5C, terminal flange 21 a may extend outwardly from the staple cartridge assembly 32 such that the stiffened region 40, shown as ruffles 41 a, provide stability around the edges of the staple cartridge assembly 32. The flange and/or ruffled portion disclosed herein can be included in any of the embodiments disclosed herein. Furthermore, the flange and/or the ruffled portion can be provided as a resilient material that resiliently engages the stapling apparatus or instrument. Furthermore, the flange and/or ruffled portion can be provided as a material having a desirable frictional characteristic for frictionally engaging the stapling apparatus or instrument.

As shown in FIG. 6A-6C, surgical buttress 24 may include an interior flange 21 b annularly extending into aperture 29 of surgical buttress 24. In embodiments, as shown in FIG. 6B, interior flange 21 b may be joined to an inner side surface 25 b of the staple cartridge assembly 32 via stiffened region 40. Alternatively, as shown in FIG. 6C, internal flange 21 b may extend inwardly into aperture 29 such that the stiffened region 40, shown as ruffles 41 b, provide stability around the inner edges of the staple cartridge assembly 32. The interior flange and/or ruffled portion disclosed herein can be included in any of the embodiments disclosed herein. Furthermore, the flange and/or ruffled portion can be provided as a resilient material that resiliently engages the stapling apparatus or instrument. Furthermore, the flange and/or the ruffled portion can be provided as a material having a desirable frictional characteristic for frictionally engaging the stapling apparatus or instrument.

A surgical buttress of the present disclosure may include perforations or cut zones around and/or through the stiffened region to allow the surgical buttress to release by breaking the perforations or cut zones when a specified amount of force is applied thereto. Such perforations or cut zones can be included in any of the embodiments disclosed herein. Perforations or cut zones allow for repeatable separation of the surgical buttress from the staple cartridge and/or anvil assembly, and would allow for stronger attachment of a surgical buttress by the stiffened region while also reducing the risk of movement or detachment prior to firing of the surgical stapling apparatus. As detachment is effected by breaking the perforations, knife cutting of the surgical buttress is not required for buttress release and thus, increased firing forces may not be required.

Perforations may be formed by placing a surgical buttress between two knife blades with the spacing between the blades corresponding to a percentage of the average thickness of the surgical buttress. The knife blade spacing could be tailored in the range of about 10% to about 100% of the average thickness of the surgical buttress, in embodiments, from about 20% to about 90% of the average thickness, and in some embodiments, about 30% of the average thickness, to ensure that the surgical buttress is well secured during insertion but break away from the stiffened regions upon firing of the surgical stapling apparatus.

As illustrated in FIG. 7A, in one embodiment, a surgical buttress 24 includes at least one stiffened region 40 disposed radially outward of the annular row of staples 50 (FIG. 1B) and perforations 27 extending around the periphery of the stiffened regions 40. Upon firing the surgical stapling apparatus (FIGS. 1A and 1B), the knife 30 (FIG. 1B) disposed within the staple cartridge assembly 32 (FIG. 1B) will impact or penetrate the surgical buttress 24 and allow the portions of the surgical buttress 24 to separate from the stiffened regions 40, via perforations 27, and pull apart from the stiffened regions which are adhered to the staple cartridge assembly 32 (FIG. 1B).

In another embodiment, shown in FIG. 7B, a surgical buttress 24 includes at least one stiffened region 40 disposed radially inward of the annular row of staples 50 (FIG. 1B) and perforations 27 extending in a circumferential line through the stiffened regions 40. Upon firing the surgical stapling apparatus (FIGS. 1A and 1B), the knife 30 (FIG. 1B) disposed within the staple cartridge assembly 32 (FIG. 1B) will impact or penetrate the surgical buttress 24 separating a portion of the surgical buttress 24 extending radially outward of the perforations 27 from the portion of the surgical buttress 24.

It is envisioned that other configurations of perforations may be provided within a surgical buttress. For example, FIG. 7C illustrates a surgical buttress including at least one stiffened region 40 a disposed radially inward of the annular row of staples 50 (shown in phantom) and at least one stiffened region 40 b disposed radially outward of the annular row of staples 50. Perforations 27 a and 27 b are provided between stiffened regions 40 a and 40 b. In embodiments, the perforations 27 a and 27 b form a circumferential perforation line separating a middle portion 44 of the surgical buttress 24 from the inner and outer portions 42, 46, respectively, of the surgical buttress 24 such that the middle portion 44 can be stapled to tissue while the inner and outer portions 42, 46 remains with the staple cartridge assembly 32.

The surgical buttress of the present disclosure may be adapted for use with other surgical stapling apparatus in accordance with the present disclosure, such as the surgical stapling apparatus disclosed in commonly owned U.S. Pat. Nos. 6,330,965 and 6,241,139, the entire contents of which are incorporated by reference herein. For example, surgical stapling apparatus for both laparoscopic and/or endoscopic surgical procedures that include an elongated body and a tool assembly for applying a linear row or rows of staples can have a buttress as disclosed in any of the embodiments hereof. Apparatus for applying a linear row or rows of staples that are arranged for open surgical procedures can also have any of the buttresses disclosed in any of the embodiments discussed herein. Apparatus having a distal end adapted to releasably engage a disposable loading unit can be used, or apparatus having removable and replaceable cartridges can be used, with the surgical buttresses disclosed herein.

As illustrated in FIGS. 8A and 8B, an exemplary surgical stapling apparatus or surgical stapler 100 for use in stapling tissue and applying a buttress material or surgical buttress to the tissue. Surgical stapling apparatus 100 generally includes a handle 112 having an elongate tubular member 114 extending distally from handle 112. A jaw assembly 116 is mounted on a distal end 118 of elongate tubular member 114. Jaw assembly 116 includes a staple clinching anvil jaw member 120 and a receiving jaw member 122 configured to receive a staple cartridge assembly 132. Jaw assembly 116 may be permanently affixed to elongate tubular member 114 or may be detachable and thus replaceable with a new jaw assembly 116. Staple clinching anvil jaw member 120 is movably mounted on distal end 118 of jaw assembly 116 and is movable between an open position spaced apart from staple cartridge jaw member 122 to a closed position substantially adjacent staple cartridge jaw member 122.

Surgical stapling apparatus 100 further includes a trigger 133 movably mounted on handle 112. Actuation of trigger 133 initially operates to move anvil jaw member 120 from the open to the closed position relative to staple cartridge jaw member 122 and subsequently actuates surgical stapling apparatus 100 to apply lines of staples to tissue. In order to properly orient jaw assembly 116 relative to the tissue to be stapled, surgical stapling apparatus 100 is additionally provided with a rotation knob 134 mounted on handle 112. Rotation of rotation knob 134 relative to handle 112 rotates elongate tubular member 114 and jaw assembly 116 relative to handle 112 so as to properly orient jaw assembly 116 relative to the tissue to be stapled.

A driver 136 is provided to move anvil jaw member 120 between the open and closed positions relative to staple cartridge jaw member 122. Driver 136 moves between a longitudinal slot 138 formed in anvil jaw member 120. A knife (not shown) is associated with driver 136 to cut tissue captured between anvil jaw member 120 and staple cartridge jaw member 122 as driver 136 passes through slot 138.

As illustrated in the current embodiment and shown in FIG. 8B, the surgical buttress 124 is releasably attached to the staple cartridge assembly 132 and/or the anvil jaw member 120 by at least one stiffened region 140 that bonds the surgical buttress 124 to the inwardly facing or tissue contacting surface 126 of the staple cartridge 132 and/or the anvil jaw member 120, in a manner similar to the bonds securing surgical buttresses 24 to the staple cartridge assembly 32, as described above.

The surgical buttress of the present disclosure, in particular surgical buttress 124, may also be adapted for use with a surgical stapling apparatus, such as that shown and described in U.S. Pat. No. 7,334,717, entitled “Surgical Fastener Applying Apparatus,” the entire content of which is incorporated herein by reference. As illustrated in FIG. 9, surgical stapling apparatus 210 includes an anvil receiving section 220 and a cartridge receiving section 222. A surgical buttress (not shown) may be attached to at least one of an anvil 221 coupled to the anvil receiving section 220, a staple cartridge assembly 232 coupled to the cartridge receiving section 222, or both, as discussed above, by at least one stiffened region. The anvil receiving section 220 and the cartridge receiving section 222 are pivotally connected via handles 212, 213 for approximation during use. Following approximation of the anvil receiving section 220 and the cartridge receiving section 222, the surgical stapling apparatus 210 is fired by driving a firing slide 236 distally through the advancement of a firing lever 233. Distal movement of the firing slide 233 causes a plurality of cam bars to engage camming surfaces that interact with a plurality of pushers to expel a plurality of surgical staples (not shown) from the cartridge receiving section 222. The staples are positioned on either side of a track which guides a knife (not shown) during longitudinal movement. The force of the knife being fired breaks the bonds between the surgical buttress and the staple cartridge, for example, created by the stiffened region between the surgical buttress and the staple cartridge, thereby releasing the surgical buttress from the staple cartridge, and severs tissue along a cut-line.

The surgical buttress of the present disclosure, in particular surgical buttress 124, may also be adapted for use with a transverse surgical stapling apparatus 310, as illustrated in FIG. 10. An exemplary transverse surgical stapling apparatus is shown and described in U.S. Pat. No. 5,964,394, entitled “Surgical Fastener Applying Device,” the entire content of which is incorporated herein by reference. The surgical stapling apparatus 310 includes an approximation lever 333, a movable handle 312, an elongated portion 314 that extends distally from the handle 312, and an arm 322 that extends from a distal end 315 of the elongated portion 314. The surgical stapling apparatus 310 further includes an anvil 321 that is orthogonally affixed to the arm 322, and a cartridge receiver 320 that is operatively coupled to the distal end 315 of the elongated portion 314 for retention of a staple cartridge assembly 332. A surgical buttress (not shown) may be joined to at least one of the anvil 321, staple cartridge assembly 332, or both as discussed above, via a stiffened region.

In embodiments, at least one bioactive agent may be combined with a surgical buttress of the present disclosure. The at least one bioactive agent may be disposed on a surface of the surgical buttress and/or impregnated therein. In these embodiments, the surgical buttress can also serve as a vehicle for delivery of the bioactive agent. The term “bioactive agent”, as used herein, is used in its broadest sense and includes any substance or mixture of substances that have clinical use. Consequently, bioactive agents may or may not have pharmacological activity per se, e.g., a dye, or fragrance. Alternatively a bioactive agent could be any agent which provides a therapeutic or prophylactic effect, a compound that affects or participates in tissue growth, cell growth, cell differentiation, an anti-adhesive compound, a compound that may be able to invoke a biological action such as an immune response, or could play any other role in one or more biological processes. It is envisioned that the bioactive agent may be applied to the surgical buttress in any suitable form of matter, e.g., films, powders, liquids, gels and the like.

Examples of classes of bioactive agents which may be utilized in accordance with the present disclosure include anti-adhesives, antimicrobials, analgesics, antipyretics, anesthetics, antiepileptics, antihistamines, anti-inflammatories, cardiovascular drugs, diagnostic agents, sympathomimetics, cholinomimetics, antimuscarinics, antispasmodics, hormones, growth factors, muscle relaxants, adrenergic neuron blockers, antineoplastics, immunogenic agents, immunosuppressants, gastrointestinal drugs, diuretics, steroids, lipids, lipopolysaccharides, polysaccharides, and enzymes. It is also intended that combinations of bioactive agents may be used.

Other bioactive agents which may be included as a bioactive agent in the surgical buttress of the present disclosure include: local anesthetics; non-steroidal antifertility agents; parasympathomimetic agents; psychotherapeutic agents; tranquilizers; decongestants; sedative hypnotics; steroids; sulfonamides; sympathomimetic agents; vaccines; vitamins; antimalarials; anti-migraine agents; anti-parkinson agents such as L-dopa; anti-spasmodics; anticholinergic agents (e.g. oxybutynin); antitussives; bronchodilators; cardiovascular agents such as coronary vasodilators and nitroglycerin; alkaloids; analgesics; narcotics such as codeine, dihydrocodeinone, meperidine, morphine and the like; non-narcotics such as salicylates, aspirin, acetaminophen, d-propoxyphene and the like; opioid receptor antagonists, such as naltrexone and naloxone; anti-cancer agents; anti-convulsants; anti-emetics; antihistamines; anti-inflammatory agents such as hormonal agents, hydrocortisone, prednisolone, prednisone, non-hormonal agents, allopurinol, indomethacin, phenylbutazone and the like; prostaglandins and cytotoxic drugs; estrogens; antibacterials; antibiotics; anti-fungals; anti-viral s; anticoagulants; anticonvulsants; antidepressants; antihistamines; and immunological agents.

Other examples of suitable bioactive agents which may be included include viruses and cells, peptides, polypeptides and proteins, analogs, muteins, and active fragments thereof, such as immunoglobulins, antibodies, cytokines (e.g. lymphokines, monokines, chemokines), blood clotting factors, hemopoietic factors, interleukins (IL-2, IL-3, IL-4, IL-6), interferons (β-IFN, (α-IFN and γ-IFN), erythropoietin, nucleases, tumor necrosis factor, colony stimulating factors (e.g., GCSF, GM-CSF, MCSF), insulin, anti-tumor agents and tumor suppressors, blood proteins, gonadotropins (e.g., FSH, LH, CG, etc.), hormones and hormone analogs (e.g., growth hormone), vaccines (e.g., tumoral, bacterial and viral antigens); somatostatin; antigens; blood coagulation factors; growth factors (e.g., nerve growth factor, insulin-like growth factor); protein inhibitors, protein antagonists, and protein agonists; nucleic acids, such as antisense molecules, DNA and RNA; oligonucleotides; polynucleotides; and ribozymes.

In embodiments, a reinforcement member may be positioned within or over a surgical buttress. In embodiments utilizing a multilayered surgical buttress, one or more reinforcement members may be positioned between, within, or at an external surface of a layer of the surgical buttress as are disclosed, for example, in U.S. Patent Application Publication No. 2009/0001122, referenced above.

Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying figures are non-limiting exemplary embodiments, and that the description, disclosure, and figures should be construed merely exemplary of particular embodiments. It is to be understood, therefore, that the present disclosure is not limited to the precise embodiments described, and that various other changes and modifications may be effected by one skilled in the art without departing from the scope or spirit of the disclosure. Additionally, it is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another exemplary embodiment without departing from the scope of the present disclosure, and that such modifications and variations are also intended to be included within the scope of the present disclosure. Accordingly, the subject matter of the present disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. 

1. (canceled)
 2. A surgical stapling apparatus, comprising: a tubular body having a distal end portion; a staple cartridge coupled to the distal end portion of the tubular body, the staple cartridge including a tissue contacting surface; and a surgical buttress including a buttress body having a first rigidity and at least one stiffened region defined in the buttress body having a second rigidity greater than the first rigidity, the buttress body including an inner portion, an outer portion, and a middle portion disposed between the inner and outer portions, the at least one stiffened region disposed in the inner or outer portion of the buttress body, the at least one stiffened region attached to the tissue contacting surface of the staple cartridge to releasably secure the surgical buttress to the staple cartridge.
 3. The surgical stapling apparatus according to claim 2, wherein the tissue contacting surface of the staple cartridge defines staple retaining slots therein, and the inner portion of the buttress body is disposed radially inward of the staple retaining slots, the outer portion of the buttress body is disposed radially outward of the staple retaining slots, and the middle portion of the buttress body extends over the staple retaining slots.
 4. The surgical stapling apparatus according to claim 3, wherein the at least one stiffened region extends continuously around the inner or outer portion of the buttress body.
 5. The surgical stapling apparatus according to claim 3, wherein the at least one stiffened region includes a plurality of stiffened regions extending around the inner or outer portion of the buttress body in spaced relation relative to each other.
 6. The surgical stapling apparatus according to claim 3, wherein the at least one stiffened region includes a first stiffened region disposed in the inner portion of the buttress body and a second stiffened region disposed in the outer portion of the buttress body.
 7. The surgical stapling apparatus according to claim 3, wherein the surgical buttress includes perforations disposed in a circumferential line extending through the at least one stiffened region.
 8. The surgical stapling apparatus according to claim 3, wherein the surgical buttress includes perforations disposed in a circumferential line between the at least one stiffened region and the middle portion of the buttress body.
 9. The surgical stapling apparatus according to claim 5, wherein the surgical buttress includes perforations around each stiffened region of the plurality of stiffened regions.
 10. The surgical stapling apparatus according to claim 6, wherein the surgical buttress includes perforations separating the first and second stiffened regions from the middle portion of the buttress body.
 11. A staple cartridge assembly for use with a surgical stapling apparatus, the staple cartridge assembly comprising: a staple cartridge including a tissue contacting surface; and a surgical buttress including a buttress body having a first rigidity and at least one stiffened region defined in the buttress body having a second rigidity greater than the first rigidity, the buttress body including an inner portion, an outer portion, and a middle portion disposed between the inner and outer portions, the at least one stiffened region disposed in the inner or outer portion of the buttress body, the at least one stiffened region attached to the tissue contacting surface of the staple cartridge to releasably secure the surgical buttress to the staple cartridge.
 12. The staple cartridge assembly according to claim 11, wherein the tissue contacting surface of the staple cartridge defines staple retaining slots therein, and the inner portion of the buttress body is disposed radially inward of the staple retaining slots, the outer portion of the buttress body is disposed radially outward of the staple retaining slots, and the middle portion of the buttress body extends over the staple retaining slots.
 13. The staple cartridge assembly according to claim 12, wherein the at least one stiffened region extends continuously around the inner or outer portion of the buttress body.
 14. The staple cartridge assembly according to claim 12, wherein the at least one stiffened region includes a plurality of stiffened regions extending around the inner or outer portion of the buttress body in spaced relation relative to each other.
 15. The staple cartridge assembly according to claim 12, wherein the at least one stiffened region includes a first stiffened region disposed in the inner portion of the buttress body and a second stiffened region disposed in the outer portion of the buttress body.
 16. The staple cartridge assembly according to claim 12, wherein the surgical buttress includes perforations disposed in a circumferential line extending through the at least one stiffened region.
 17. The staple cartridge assembly according to claim 12, wherein the surgical buttress includes perforations disposed in a circumferential line between the at least one stiffened region and the middle portion of the buttress body.
 18. The staple cartridge assembly according to claim 14, wherein the surgical buttress includes perforations around each stiffened region of the plurality of stiffened regions.
 19. The staple cartridge assembly according to claim 15, wherein the surgical buttress includes perforations separating the first and second stiffened regions from the middle portion of the buttress body. 